■S:/ir 


Circular  No.  1 15. 


United  States  Departing 


BUREAU   OF   E 
L.  O.  HOWARD,   Entomolog 


THE   HORN   Ffr 

Hi  matobia  serrata  Rob.-Desv.) 

By  C.  L.  Marlatt,  M.  S., 

Issistant  Entomologist  and  Acting  ChieJ  in  Absena  of  Chief . 

INTRODUCTION    AM)    SPREAD. 

The  horn  fly  is  one  of  the  worst  of  the  European  biting  Hies  that 
attack  cattle,  but,  curiously  enough,  it  failed  to  reach  this  continent 
until  a  comparatively  late  date,  notwithstanding  abundant  impor- 
tations of  live  stuck  from  Europe  during  nearly  three  centuries.     It 


KIG.  1.  ilxmatobia  srrratu         I  larva;  e,  puparium;  d,  adult  in  resting  position.    Much 

enlarged.    (From  Riley  and  Howard.) 

was  first  discovered  and  reported  to  this  Bureau  in  the  fall  of  1887 
as  occurring  near  Camden,  N.  .1.  The  following  year  it  appeared  in 
Maryland  and   Virginia,   and   thereafter,  spread   rather  rapidly,  and 

\>\    1891     L892  it   \\:i^  found  over  the  continent   front  Canada  to  ¥qxas 
■    115— 10 


and  from  Massachusetts  to  the  Rocky  Mountains.  It  has  not  heen 
reported  as  an  especially  injurious  pest  in  California,  but  undoubtedly 
occurs  there,  and  was  carried  with  cattle  from  the  western  coast  of 
the  United  States  to  Honolulu  in  1897.  The  following  year  it  had 
spread  to  all  the  islands  of  the  Hawaiian  group,  and,  under  a  favoring 
climate  which  permits  multiplication  to  go  on  the  3Tear  round,  it  had 
become  a  perhaps  worse  pest  on  these  islands  in  the  middle  of  the 
Pacific  than  in  the  United  States. 

The  fust  appearance  of  the  fly  in  New  Jersey  and  Pennsylvania 
makes  it  evident  that  it  was  brought  to  this  country  on  European 
cattle  in  the  early  eighties.  In  the  first  publications  on  the  subject 
it  was  stated  that  the  fly  was  probably  brought  in  through  the  port 
of  Philadelphia  in  1886,  but  the  records  of  the  Bureau  of  Animal  Indus- 
try indicate  that  the  importation  of  cattle  through  Philadelphia  was 
discontinued  early  in  1885.  From  this  fact  either  the  fly  was 
imported  a  year  or  more  earlier  than  has  hitherto  been  supposed,  or 
else  the  fly  must  have  come  with  cattle  through  some  other  port, 
probably  New  York.  The  former  supposition,  from  the  early  records 
of  distribution  of  the  fly,  seems  the  more  likely. 

EARLY    INVESTIGATIONS. 

The  early  records  of  the  horn  fly  in  1887  and  1888  gave  little  indi- 
cation of  its  future  importance  to  stockmen,  but  in  18S9  much  ex- 
citement was  aroused  by  the  pest  in  New  Jersey  and  throughout 
Maryland  and  in  Virginia  by  the  rapid  spread  of  the  fly  and  the 
excessive  damage  from  it  to  cattle.  This  Bureau  at  once  began  a 
thorough  investigation  of  the  subject,  largely  conducted  by  Dr. 
L.  O.  Howard,  assisted  by  the  writer,  and  the  life  history  and  habits 
of  the  insect  were  worked  out  with  fair  thoroughness  during  this  year.a 
In  the  same  year  it  was  being  studied  in  New  Jersey  by  Prof.  J.  B. 
Smith,6  and  during  the  years  immediately  following  it  was  the  subject 
of  investigation  and  report  by  most  of  the  official  entomologists  of 
this  country  and  Canada.  More  recently  it  has  beenstudied  in  Hawaii 
by  D.  L.  Van  Dine  and  Jacob  Kotinsky,  and  the  rearing  of  parasites 
and  other  natural  enemies  has  been  undertaken  in  Texas  by  agents  of 
this  Bureau  for  the  benefit  of  and  in  cooperation  with  the  Hawaiian 
authorities. 

The  fly  was  early  determined  as  the  European  cattle-biting  fly 
named  above,  as  the  result  of  submitting  material  to  eminent  Dip- 
terologists  of  this  country  and  abroad.  The  insect  was  originally 
described  from  southern  France,   and  its  rapid  spread   and  greater 

"insect  Life,  Vol.  II,  pp.  93-103;  Ann.  Rep.  Dept.  Agr.  for  1889,  ]>p.  315-348. 
'<  Bui.  62,  N.J.  Agr.  Exp.  Sta.,  L889 

I  fir.  115] 


damage  in  this  countrj  in  its  southward  range  would  indicate  t  lint 
it  is  a  southern  European  species.  This  fad  maj  account  for  the 
late  date  of  its  introduction  to  America,  the  chief  importations  of 
cattle  coming  from  central  or  northern  Europe. 

I  (>\I\K>\     \  \\1  ES. 

The  name  "horn  fly"  was  given  ii  at  the  very  start,  from  its  ha  hit, 
especially  early  in  the  season,  of  settling  in  large  numbers  around  the 
base  of  the  horns,  and  it  i-  imu  everywhere  known  by  this  name. 
For  the  first  few  year-,  when  the  fact  of  it-  being  a  new  pest  was  not 
fully  appreciated,  various  name-  were  given  it,  some  of  which  applied 
to  other  biting  gnats,  such  as  "buffalo  fly,"  "buffalo  gnat,"  and 
"Texas  horn  fly."  The  name  "horn  fly"  is  so  appropriate  that  the 
others  were  short-lived,  hut  this  name  carries  a  slight  chance  of 
misunderstanding,  inasmuch  a-  the  insect  does  not  affect  the  horn, 
but  simply  chooses  this  point  a-  a  resting  place  when  it  is  inactive — 
largely  because  the  base  and  inner  curve  of  the  horn  is  a  point  which 
the  animal  can  not  reach,  either  1>\  swinging  the  head  from  side  to 
side  or  with  the  tail,  to  dislodge  the  Hie-. 

Tin;    DAMAGE    OCCASIONED    BY    THE    HORN    111 

The  horn  fly  i-  a  blood-sucking  insect,  hut  the  damage  occasioned 
by  it  is  chiefly  the  result  of  the  irritation  to  cattle  which  prevents 
proper  feeding  and  normal  assimilation  of  food,  and  hence  loss  of 
flesh  di'  lessened  milk  production.  There  is  also  the  actual  loss  of 
blood,  which  may  he  considerable  when  these  Hie-  are  abundant. 
The  injury  by  the  fly  in  New  Jersey,  Maryland,  and  Virginia  during 
the  first  year  after  it-  introduction  was  very  considerable,  and  this 
is  true  of  its  first  appearance  in  the  wider  and  wider  areas  covered 
by  it.  After  a  year  or  two,  however,  the  cattle  perhaps  became 
more  used  t<>  it,  and  the  natural  enemies  of  other  Diptera.  beginning 
to  attack  it.  reduced  its  nunihers  to  some  extent,  so  that  the  loss 
from  it  was,  as  a  rule,  much  lessened.  Particularly  in  the  West  and 
Southwest,  however,  the  damage  from  the  horn  fly  continues  to  be  of 
very  serious  moment. 

Dining  the  first  year-  of  the  horn  fly,  when  it  was  a  new  and 
little  understood  menace  to  cattle,  the  losses  occasioned  by  it  were 
undoubtedly  much  exaggerated.  Nevertheless  the  I..--.  when  the  fly 
is  abundant,  is  still  very  considerable,  showing  in  reduced  vitality, 
lack  of  growth,  or  lessened  yield  of  milk,  the  production  of  milk  often 
being  cut  down  from  one-fourth  to  one-half.  In  Canada  the  late 
Dr.  dame-  Fletcher  estimated  the  loss,  in  Ontario  and  Quebec,  at 
one-half  of  the  product  of  meat  and  milk. 
I  fir.  1  15] 


The  horn  fly  exhibits  a  certain  preference  for  red  or  other  dark- 
colored  cattle,  and  that  such  animals  are  more  thickly  infested  has 
been  frequently  noted.  When  the  insects  are  abundant,  however, 
this  preference  is  not  so  strongly  marked.  Occasionally  sores  are 
formed  on  the  animals,  which  in  the  South  and  West  may  become 
infested  with  the  screw  worm  (Chrysomyia  macellaria  Fab.).  These 
wounds  or  sores  are,  as  a  rule,  only  indirectly  the  result  of  horn-fly 
attacks,  but  are  commonly  produced  by  the  rubbing  of  the  cattle  in 
efforts  to  allay  the  irritation  from  the  bites. 

The  loss  occasioned  by  the  horn  fly  to  other  animals  is,  as  a  rule, 
inconsiderable.  Sometimes  horses  are  attacked,  and  especially  cow 
ponies,  and  injury  to  sheep,  as  pointed  out  by  Norgaard,"  is  compli- 
cated with  sheep  scab. 

LIFE    HISTORY    AND    HABITS. 

The  appearance  and  abundance  of  the  flies  is  governed  by  tem- 
perature and  rainfall.  In  the  latitude  of  Washington  they  are  first 
noticed  in  May,  and  become  most  abundant  in  July,  gradually 
dwindling  to  November  or  until  sharp,  frosty  nights  become  frequent. 
Farther  south  they  appear  earlier  and  remain  in  evidence  later.  The 
study  of  this  insect  in  Texas  by  agents  of  this  Bureau,  notably  Mr. 
J.  D.  Mitchell,  at  Victoria,  indicates  that  the  fly  reaches  its  first  maxi- 
mum of  abundance  in  May.  During  the  subsequent  dry  period  the 
fly  decreases  in  numbers  until  fall  rains  begin,  when  a  second  maxi- 
mum is  reached  in  late  September,  which  is  checked  by  the  frosts  of 
the  latter  part  of  October.  Continuing  on  from  then  until  March  the 
fly  is  kept  down  to  comparatively  small  numbers  by  low  tempera- 
tures. The  reduction  of  the  numbers  of  the  fly  in  Texas  by  a  dry, 
hot  summer  is  sometimes  as  great  as  95  per  cent  from  the  maximum 
of  May. 

The  characteristic  habit  of  the  fly  in  clustering  about  the  base  of  the 
horn  is  developed  only  when  the  flies  are  abundant.  When  they 
average  only  100  or  so  to  an  animal,  comparatively  few  will  be  found 
on  the  horns.  The  horn-clustering  habit  is  more  noticeable  in  the 
spring  and  early  summer  than  in  autumn.  The  horns  are  not  the 
only  resting  places,  and  many  of  the  flies  cluster  upon  the  back,  be- 
tween the  head  and  the  fore  shoulders,  where  they  can  be  reached 
by  neither  head  nor  tail.  When  the  cattle  are  feeding,  the  flies  are 
found  over  the  back  and  flank  and  on  the  legs,  and  during  a  rain- 
storm they  flock  beneath  the  belly.  When  the  animal  is  lying  down, 
a  favorite  place  of  attack  seems  to  be  under  the  thigh  and  back  belly 
around  the  udder.  The  characteristic  appearance  of  the  flies  on  the 
horn  is  indicated  in  the  accompanying  illustration  (fig.  2). 

a  Rep.  Agr.  and  Forestry,  Hawaii,  1905,  pp.  171,  211,  212. 
[Cir.  115] 


In  the  Feeding  position  the  wings  arc  slightly  elevated,  and  arc 
held  out  from  the  I >< ><  1  \  al  an  angle  of  60°  from  the  abdomen;  the 
legs  arc  held  oul  widely,  and  the  beak,  inserted  beneath  the  -kin  of 
the  animal,  is  directed  almost  perpendicularly  (see  fig.  •"».  c).  Before 
inserting  its  beak  the  |1\  works  it-,  way  through  the  hair  close  to  the 
skin,  hut  is  able  at  the  leasl  sign  of  danger  to  rise  instantly  in  (light, 
to  return  as  quickly.  The  characteristic  appearance  of  the  fly  is 
3hown in  the  accompanying  illustration  (fig.  I).  It  is  about  half  the 
size  of  the  house  fly,  which  it  closely  resembles,  hut  is  much  less 
robust. 

Differing  from  other  biting  flies,  the  horn  fly  normally  stays  on  the 
cuttle  night  and  day,  and  when  not  feeding  rests  on  the  cattle  as 
already  described. 


in..  2. — Cow-horn  showing  band  of  resting  horn  Hies.    Reduced.    (From  Riley  and  Howard.) 

I'he  egg-laying  habit  of  the  insect  was  not  easily  discovered  and  is 
somewhat  peculiar.  The  eggs  are  laid  singly  and  usually  upon  their 
sides  upon  the  surface  of  wet  dung.  The  moment  the  latter  is 
dropped,  a  swarm  of  flies  dart  from  the  animal  to  the  dung  and  re- 
main there  a  few  seconds,  or  a  minute  at  the  most,  during  which 
time  many  eggs  are  deposited.  Egg  laying  is  chiefly  during  day- 
light, between  9  a.  m.  and  1  p.  m.,  and  most  abundant  during  the 
wanner  morning  hours.  So  far  as  we  know,  they  are  laid  upon  no 
other  substance,  and  never  upon  old  dung. 

The  larva1  upon  hatching  descend  into  the  dung,  remaining,  how- 
ever, rather  near  tin1  surface.  When  full  grown  they  are  about  two- 
lift  lis  of  an  inch  in  Length  and  of  the  normal  color  and  form  of  the 
related  dung  maggots.  The  puparium  is  formed  in  the  ground  be- 
neat  h  the  dung.  The  time  elapsing  from  tin1  egg  to  the  adult  is  from 
ten  to  seventeen  days,  and  there  are  probably  seven  or  eight  genera- 
tions annually  in  t he  latitude  of  Washington,  with  more  in  the  South; 

[Cir.  115  1 


and  continuous  breeding  in  a  tropical  region  like  the  Hawaiian  Islands. 
The  winter  habits  as  studied  near  Washington,  D.  ('.,  indicate  that 
hibernation  normally  takes  place  either  in  the  adult  stage  or  as 
puparia  below  the  surface  of  the  ground. 

PARASITES    AND    NATURAL    ENEMIES. 

The  natural  enemies  of  the  horn  fly,  like  those  of  most  other  dung- 
breeding  flies,  are  destructive  to  the  insect  in  its  larval  and  pupal 
stages.  Therefore  the  bringing  over  of  the  insect  from  Europe  in  the 
adult  stage  with  cattle  resulted  necessarily  in  its  freedom  for  a  time 
from  the  control  by  such  natural  enemies.  The  similar  enemies  of 
other  dung  flies  in  this  country,  however,  undoubtedly  very  soon 
began  to  exercise  a  certain  degree  of  control,  and  this  may  account 


Fig.  3. — Horn  fly:  a,  Head  of  female,  front  view;  b,  head  of  male,  front  ■v  icw  .  c,  head  from  side 
enlarged.    (From  Riley  and  Howard.) 


(ireatlv 


somewhat,  at  least,  for  the  much' greater  damage  occasioned  by  the 
horn  fly  in  the  first  years  of  its  occurrence  in  the  different  zones  of 
its  spread  across  the  continent  than  was  the  case  during  subsequent 
years.  Very  early  after  the  appearance  of  the  horn  fly  it  was  noted 
by  Mr.  F.  M.  Webster  that  in  Ohio  fully  20  per  cent  of  the  flies  were 
infested  by  one  of  the  scarlet  mite  fly  parasites  (Gamasida*).  This 
mite  was  not  determined,  but  was  probably  one  of  the  native  species 
commonly  seen  on  other  flies. 

The  introduction  of  the  horn  fly  into  the  Hawaiian  Islands  and  the 
heavy  losses  there  occasioned  by  it  led  to  an  active  investigation  on 
the  part  of  the  island  authorities  of  parasites  and  predaceous  enemies. 
Mr.  Albert  Koebele  imported,  in  1905,  from  New  South  Wales,  quan- 
l  it  ies  of  material  from  which  dung  beetles  were  reared  and  introduced 
into  the  islands.  In  1906  Mr.  Koebele  came  to  the  United  States  and 
made  extensive  collections  of  material  in  California  and  Arizona,  and 
from  this  material  at  least  six  or  seven  .species  of  dung  beetles  were 
introduced  into  the  Hawaiian  Islands,  and  two  species  of  true  parasites. 
[Cir.  115] 


The  beetles  in  question  are  those  which  habitually  live  in  cattle  dung 
and  feed  upon  living  maggots  therein,  or  are  of  the  tumblebug 
variety  which  disintegrate  the  dung  shortly  after  deposition,  thus 
preventing  or  checking  the  breeding  of  the  flies. 

The  true  parasites  reared  from  material  sent  by  Mr.  Coebele  from 
Arizona  proved  to  be  Eucolia  impatiens  Say,  styled  "the  Arizona 
dung-fly  parasite,"  and  a  species  of  Eutrias,  styled  "the  lesser  dung- 
fly  parasite."  These  two  minute  four-winged  flies  are  undoubtedlj 
normally  enemies  of  native  dung-breeding  Hies,  but  take  readily  to 
the  horn  fly.  They  were  reared  in  considerable  numbers  and  dis- 
tributed among  the  ranchmen  on  the  islands.  It  is  too  early  yel  to 
determine  whether  these  importations  will  he  of  much  practical  value 
in  controlling  the  horn  fly. 

'Two  other  similar  minute  Hymenopterous  parasites,  belonging  to 
the  genus  Spalangia,  were  reared  by  Mr.  Kotinsky  from  pupse  of  the 
common  stable  fly    (>  *  ((licit vans  L.),  from  material  collected 

on  the  [sland  of  Hawaii.  One  of  these,  Spalangia  hirta  Haliday, 
confined  with  horn-fly  pupse,  promptly  attacked  the  latter,  and  in 
three  or  four  w  eeks  a  brood  of  these  parasites  \\  as  successfully  reared. 
Later,  horn-fly  pupa*  collected  in  the  held  were  found  parasitized  by 
this  species.  The  other  parasite,  S.  lanaiensis  Ashm.,  supposed  to 
he  a  native  species,  was  also  again  reared  from  Dipterous  pupa1. 
That   both  of  these,  will  become  important  enemies  of   the  horn  fly 

seems  to  be  established. 

MEANS    Ol     (ONI  KOI.. 

The  simple  means  of  prevention  of  abundance  of  the  Hies  by  the 
destruction  of  larvae  in  the  dung  and  the  protection  of  animals  from 
the  attacks  of  the  adults,  suggested  in  the  earlier  investigation  of  the 
subject  by  thisBureau,  have  remained  thestandard  means  of  control, 
with  some  improvements  and  amplification  enabling  them  to  be 
carried  out  on  a  larger  scale  and  at  less  cost.  There  are  two  principal 
methods  of  control  one.  the  destruction  of  the  larvSB  and  pupa-  in 
the  cattle  dung  by  direct  measures  or  by  the  act  ion  of  nat  ural  enemies 
already  discussed;  and  the  other,  the  protection  of  cattle  either  by 
the  use  of  repellent  ointments  or  by  the  actual  capture  and  destruc- 
tion of  the  adult  flies. 

Repellents.  Almost  anj  greasj  substance  will  keep  the  flies  away 
for  from  a  few   hours  to  several  days.     A  greal   many  oils  and  fats 

have  I n  experimented  with,  and  the  commercial  product  known  as 

li-.h  or  train  nil.  flrst  suggested,  remains  the  best  easily  available  oint 
iiieni.     The  protection  by  the  use  of  tin-  mixture  varies  in  different 
regions.     En  the  dry,  hot  area  of  the  West  and  Southwest  protection 
lasts  only  two  or  three  days;  in  the  more  moist  and  cooler  regions  of  the 
ii:.] 


8 

East  and  North,  five  or  six  days.  This  oil  costs  from  50  to  7o  cents 
a  gallon.  The  addition  of  a  little  sulphur  or  carbolic  acid  is  of 
benefit,  the  latter  making  the  application  somewhat  healing  if  any 
sons  have  been  formed.  Where  only  a  few  animals  are  to  be  treated, 
as  a  home  supply  of  dairy  cattle  or  a  dairy  herd,  the  application  can 
be  made  with  a  common  painter's  brush.  It  may  be  unnecessary  to 
attempt  to  protect  the  entire  animal,  but  only  those  parts  not  reached 
by  the  head  or  tail,  although  the  more  completely  the  animal  is 
covered  the  greater  will  be  the  reduction  of  loss. 

In  Virginia  Prof.  W.  B.  Alwood  found  that  animals  could  be  treated 
with  the  standard  insecticide,  kerosene  emulsion,  applied  with  a 
small  hand-spray  pump.  This  application  killed  all  the  flies  that 
were  actually  wetted  by  it  and  gave  protection  to  the  treated  animals 
for  two  daj^s.  With  a  little  tobacco  water  added  he  found  two  appli- 
cations a  week  sufficient,  using  from  1  to  2  pints  for  each  animal. 
The  application  was  made  just  after  milking,  and  was  only  tested 
on  dairy  animals. 

Kerosene  emulsion  is  prepared  after  the  following  formula.  The 
crude  oil  yields  a  stronger  and  more  lasting  product : 

Petroleum,  refined  or  crude gallons. .   2 

Whale-oil  soap  (or  1  quart  soft  soap) pound . .   J 

Water  (soft) gallon. .    1 

The  soap,  first  finely  divided,  is  dissolved  in  the  water  by  boiling 
and  immediately  added  boiling  hot,  away  from  the  fire,  to  the  oil.  The 
whole  mixture  is  then  agitated  violently  while  hot  by  being  pumped 
back  upon  itself  with  a  force  pump  and  direct  discharge  nozzle  throw- 
ing a  strong  stream,  preferably  one-eighth  inch  in  diameter.  After 
from  three  to  five  minutes'  pumping  the  emulsion  should  be  perfect, 
and  the  mixture  will  have  increased  from  one-third  to  one-half  in  bulk 
and  assumed  the  consistency  of  cream.  Well  made,  the  emulsion  will 
keep  indefinitely  and  should  be  diluted  only  as  wanted  for  use. 

In  limestone  regions,  or  where  the  water  is  very  hard,  some  of  the 
soap  will  combine  with  the  lime  or  magnesia  in  the  water,  and  more 
or  less  of  the  oil  will  be  freed,  especially  when  the  emulsion  is  diluted. 
Before  use,  such  water  should  be  broken  with  lye,  or  rain  water  should 
be  employed. 

It  may  be  used  pure  or  diluted  with  one  part  of  water  for  local 
applications  with  a  brush,  or  with  two  or  three  parts  of  water  as  a 
spray. 

A  mixture  recommended  by  the  Kansas  Experiment  Station," 
claimed  to  be  as  satisfactory  and  considerably  cheaper  than  fish  oil, 
is  made  after  the  following  formula:    Pulverized  resin,  2  parts,  by 

"Press  Bui.  No.  ti">.  March  20,  1900. 
[Clr.  l  15] 


measure;  soap  shavings,  I  part;  water,  J  pan;  fish  oil,  l  part;  oil 
of  tar,  1  part:  kerosene,  1  pari;  water,  3  parts.  Place  the  resin, 
snap  shavings,  J  pan  of  water  and  fish  oil  together  in  a  receptacle 
and  boil  till  the  resin  is  dissolved.  Then  add  3  pans  of  water,  follow- 
ing with  the  oil  of  tar  mixed  with  the  kerosene.  Stir  the  mixture 
well  and  allow  it  to  boil  for  fifteen  minutes.  When  cool  the  mixture 
is  ready  for  use,  and  should  be  si  irred  frequently  while  being  applied. 
This  mixture  costs  about  30  cents  a  gallon,  and  from  one-eighth  to 
one-half  pint    is  sulhcient   for  one  application  with  the  brush  method. 

The  methods  jus!  described  are  not  applicable  to  large  grazing  herds 
or  cattle  on  the  range. 

Fly  control  on  iht  range.  For  the  control  of  the  hom  fly  on  range 
cattle  on  a  large  scale  the  dipping--*  ats  system  employed  for  the  con- 
trol of  the  cattle  tick  or  other  skin  parasites  offers  the  best  solution 
of  the  problem.  The  oily  dips  used  for  the  Texas-fever  tick,  described 
in  a  publication  of  the  Bureau  of  Animal  [ndust  ry  of  tins  Depart  men t " 
can  he  made  to  serve  as  a  very  effective  means  of  controlling  the  horn 
fly.  It  was  early  discovered  thai  dipping  cattle  in  these  oily  mix- 
tures in  the  ordinary  way  was  of  little  service  in  destroying  the  horn 
Hies.  The  cattle  dips  were  repellent  to  the  horn  fly  lor  a  very  short 
period,  and  the  percentage  of  the  Hies  killed  by  the  operation  was 
inconsiderable.  During  the  last  three  years,  however,  Mr.  .1.  I>. 
Mitchell,  an  agent  of  this  Bureau,  working  with  Mr.  \Y.  I).  Hunter 
in  Texa>.  has.  in  a  study  of  the  requirements  for  horn-fly  control, 
found  that  by  a  very  simple  modification  of  the  ordinary  dipping 
vat  a  very  large  percentage  of  the  flies  on  the  cattle  can  he  desl  roj  ed, 
with  the  consequent  very  notable  limiting  of  the  loss  from  this  fly 
pest.  With  the  vats  as  ordinarily  constructed,  most  of  the  Hies  aban- 
don the  animal  at  the  moment  it  plunges  into  the  dip  and  escape, 
and  go  to  other  animals,  and  ultimately  with  t  he  drying  of  the  dipped 
animal  return  to  it.  Mr.  Mitchell  found,  however,  that  1>\  putting 
a  splashboard  near  the  top  of  the  vat  on  either  side,  about  4  feet 
above  the  level  of  the  dip,  the  water  thrown  up  violently  as  the 
animal  plunges  m  is  caught  by  these  splashboards  and  is  tin-own  hack 
as  a  spray,  filling  the  airspace  above  the  animal  and  drenching  and 
destroying  the  Hies  in  their  effort  to  escape.  The  few  of  the  horn 
flies  that  may  escape,  together  with  those  which  abandoned  the  animal 
at  the  entrance  to  the  vat.  were  observed  to  hover  or  settle  on  the 
chute  fence,  and  many  would  alight  on  the  next  animal  coming  along. 
I  Ie  also  found  t  hat  w  here  t  he  animals  have  been  heated  in  corralling  and 
getting  them  into  the  chute  the  I  lies  .stick  much  closer  and  are  much  less 
apt  to  take  quick  flight,  thus  insuring  the  capture  of  a  larger  percentage 

of  them  by  the  dip  and  spray. 


rmers'  Bulletin  378.  <  Ictober    I  K)9 

I  (Mr.  11.-.] 


10 


The  first  suggestion  of  splashboards  was  not  as  a  means  of  con- 
trolling the  horn  fly  but  to  keep  the  fluid  from  wasting  over  the  sides 
of  the  vat  and  to  protect  the  men  who  were  wTorking  near  the  vat. 
When  a  large  animal  strikes  the  fluid  the  splash  will  fly  as  high  as 
6  feet,  and  the  spray  will  scatter  widely. 

The  accompanying  detailed  sketches  illustrate  two  vats  equipped 
with  splashboards  which  have  been  used  very  successfully  for  a  num- 
ber of  years  in  Texas.  The  first  sketch  (fig.  4)  is  a  cross  section  of  the 
vat  constructed  by  Mr.  J.  J.  Welder,  Victoria  County,  Tex.  A  ground 
plan  of  the  entrance  is  illustrated  in  figure  5.  Mr.  Welder's  vat  is  a 
rather  large  one,  having  a  surface  level  of  the  dip  5  feet  wide  but  wTith 

an  entrance  chute  to  the 
vat  of  only  3  feet  and 
9  inches.  The  splash- 
boards are  2  feet  wide 
and  20  feet  long,  ex- 
tending from  the  termi- 
nation of  the  entrance 
chute.  In  the  case  of 
this  dipping  vat  the  ani- 
mal is  confined  to  the 
middle  of  the  vat  and 
entirely  away  from  the 
splashboards  b}7  the  nar- 
row entrance  chute. 

Another  similar  vat 
is  illustrated  in  figure 
6.  This  vat  wTas  con- 
structed by  Mr.  A.  P. 
Borden  on  the  Pierce 
Ranch,Wharton  County , 
Tex.  The  splashboards 
are  1  foot  wide  and  ex- 
tend the  full  length  of 
the  vat,  andean  be  used,  if  necessary,  as  a  walk  in  assisting  cattle  in 
trouble.  The  ends  of  the  splashboards  next  to  the  entrance  arc 
rounded  off  in  the  case  of  this  vat;  but  the  entrance  slides,  as  illus- 
trated in  the  ground  plan  of  the  Welder  vat  (fig.  5),  and  the  height  of 
(he  splashboards  above  the  dip  level,  have  in  the  actual  treating  of 
hundreds  of  cattle  prevented  any  difficulty  of  catching  or  colliding 
of  the  animals  with  the  splashboards,  and  were  used  on  a  number  of 
\  als  in  Texas  most  successfully  during  the  years  1907  to  1909. 
[Cir.  115] 


-Cross  section  of  dipping  vat  used  by  Mr.  J..  T.  Welder. 
(Original). 


11 


EE 


ta» 


3 


IB 


With  vats  equipped  like  the  above,  from  75  to  80  per  cent  of  the 
horn  flics  mi  the  cattle  are  destroyed." 

Mr.  Hunter  experimented  with  a  small  model  of  a  dipping  vat,  and 
1'ou  in  I  that  if  the  splash  were  received  on  a  slightly  curved  galvanized 
iron  sheet  instead  of  a  hoard  it  was  considerably  more  effective  in  dis- 
tributing the  hack  throw  of  the  \\  ater  in  the  form  of  an  efficienl  spray. 

The  arsenical  dips  used  for  the  cattle  tick  would  have  comparative!} 
little  value  for  the  horn  fly  except  thai  very  likely  a  good  many  flies 
might  he  caughl  and  destroyed  bj  merely  being  wetted  with  the  dip. 

A  similar  treat 
incut  has  recentl} 
been  the  subject  of 
experiment  in  the 
West .  An  apparatus 
has  been  con 
structed,  designed 
in  0  r  e  part  icularly 
for  the  destruction 
Of   skin    parasites    of 

cattle,  to  supplant 
the  old  method  of 
dipping  in  a  vat.  It 
has  been  suggested 
that  this  apparat  us 
will  furnish  a  ver\ 
good  means  of  con 
trol  in  the  case  of 
the  horn  fly.  The 
probabilities  are. 
however,  from  the 
experience  with  the 
horn-fly  traps  re- 
ferred to  below,  that  most  of  the  flies  would  abandon  t  he  cat  t  le  at  the 
moment  of  entrance  to  the  cylinder,  and  its  efficiency  as  a  means  of 
horn-fly  control  i^  very  problematical. 

The  process  consists  in  driving  the  animals  t  hrough  a  large  cylinder 
through  the  sides  of  which  a  powerful  gasoline  pump  causes  sprays 
of  the  insecticide  to  strike  the  animals  from  all  quarters  and  thor- 
oughly wet  them.  This  machine  is  patented  and  is  sold  at  a  rather 
excessive  price.     The  liquid  used  i>  an  emulsion  of  crude  petroleum 

l  or  further  details  of  the  construction  of  dipping  va  1  urmers'  Bulletin  378, 

"Methods  "i"  Exterminating  the  Texas  Cattle  Tick,"  by  II.  W.  Graybill,  Bur 
Animal  Industry      In  the  case  of  the  val  there  described,  in  successfully  use  the 
splashboard  ii  may  be  necessary  i"  increase  the  height  of  il  the  vat  so  that 

i lie  splashboards  can  lie  placed  i  feet  or  a  little  more  above  the  level  of  the  dip 
ii:,] 


JilJJkniIIDi 


Km..: 


Ground  plan  of  dipping  vat  used  by  Mr.  J.  J.  Welder. 


IE 


(Original.) 


12 


in  water  in  the  proportion  of  20  gallons  of  oil  to  80  gallons  of  water, 
with  the  addition  of  5  pounds  of  soap.  This  apparatus  is  claimed  to 
be  able  to  take  care  of  from  3,000  to  4,000  head  of  cattle  per  day. 
With  this  or  some  similar  device  the  control  of  the  horn  fly  ou  a 
broader  scale  may  prove  practicable. 

Horn-fly  traps.- — Various  attempts  have  been  made  to  collect  horn 
flies  from  cattle  by  means  of  traps,  the  general  plan  being  to  pass  the 


Fig.  6.— Cross  section  of  dipping  vat  used  by  Mr.  A.  P.  Borden.    (Original.) 

cattle  through  a  dark  room  or  chamber  arranged  with  brushes  at 
the  exit  to  drive  the  flies  from  the  cattle  and  retain  them  in  the 
chamber,  where  they  may  be  attracted  to  a  lighted  cupola,  captured, 
and  destroyed.  Mr.  P.  J.  Parrot t,  while  connected  with  the  Kansas 
Experiment  Station,  conducted  elaborate  experiments  in  this  direc- 

rCir.  1151 


i:: 

tion."  hut  the  results  were  most  unsatisfactory,  the  great  majority 
of  the  flies  abandoning  the  cattle  al  the  moment  of  entrance,  so  thai 
onlj  about    •">  per  cent  of  the  flies  were  captured. 

Destruction  of  larva  and  pupx.  The  destruction  of  larva'  and 
pupae  in  the  dung  by  direct  measures  and  consequent  reduction  in 
the  numbers  of  the  adult  insects  is  a  possible  means  of  control,  not, 
however,  always  practicable,  and  having  little  utility  in  the  case  of 
range  animals.  Two  methods  of  locally  destroying  the  Hies  in  the 
dung  have  been  shown  to  be  fairly  effective.  A  spadeful  of  lime 
thrown  on  com  dung  will  destroy  the  larvae  living  in  it,  and  in  small 
past  ures  such  treat  mi 'nt  of  dung,  especially  at  points  where  the  cattle 
arc  more  apl  to  congregate,  may  be  feasible.  Tins  treatment  is  espe- 
cially useful  if  carried  out  during  May  and  dune,  as  every  larva  killed 
of  the  early  broods  means  a  very  large  reduction  in  the  number  of 
flies  for  midsummer  and  later  in  the  season. 

Prof.  J.  B.  Smith  suggests  another  means  of  control,  namely,  the 
spreading  out  of  the  fresh  dung  with  a  shovel,  w  Inch  causes  the  rapid 
drying  of  the  dung  and  the  destruction  of  the  Dipterous  larvae  con- 
tained in  it.  This  method  also  is  feasible  only  in  the  case  of  small 
pastures  and  in  dry  weather.  An  inexpensive  method,  suggested 
h\  Mr.  D.  L.  Van  Dine,  of  scattering  the  dung  in  yards  and  pens  and 
causing  it  to  dry  quickly  is  to  allow  a  number  of  pigs  to  run  with  the 
cattle.  In  their  efforts  to  obtain  undigested  particles  of  food  the 
pigs  will  ell'cctualU  destroy  the  dung  as  breeding  places  for  the  fly, 
at  least  during  dry  periods. 

A  dairyman  in  Texas,  as  reported  by  Mr.  J  hint  or.  has  followed  an 
analogous  method  of  control  which  has  given  him  very  considerable 
protection  from  the  horn  fly.  He  makes  it  a  practice  to  collect 
daily  the  dung  in  and  near  the  dairy  barns,  and  every  few  days  this 
collected  materia]  is  taken  out  and  distributed  with  a  spreading 
machine  on  t  he  past  ure,  so  thai  it  promptly  dries  up  and  the  breeding 
of  larva'  in  it  i^  prevented.  Wherever  this  practice  i-  feasible  it  is 
to  be  strongly  recommended,  and  has  the  important  additional  argu- 
ment in  its  favor  of  conserving  the  valuable  manurial  materia]  which 
might  otherwise  <jo  t"  waste. 

In  the  same  way,  as  observed  by  Mr.  Mitchell,  during  the  dry 
period  of  July  and  August  in  western  Texas  the  horn  fly  i>  very  much 
reduced  in  numbers  by  the  rapid  desiccation  of  the  cow  droppintrs. 

Approved : 
James  Wilson, 

tary  of  Agricvll 

Washington,  1>  C     November  17,  1909. 

a  Kansas  State  Agr.  Coll.  Exp   Sta     Pre     Bui.  No.  19,  November  7,  1899. 
( Clr.  it.".] 

o 


UNIVERSITY  OF  FLORIDA 


3  1262  09216  5124 


